Case History

Larson determined that a one-piece cylinder design with a heavier wall thickness would solve the defined problems and meet the higher pressure rating required by U.L. The cost of the cylinder could not increase, despite added material cost due to heavier wall thickness. Direct labor costs would have to be reduced significantly. The manufacturing processes employed for this product had to be innovative and cost effective, to make the cylinder economically viable.

The staff at Larson developed a set of design parameters to meet the customer’s requirements as well as the U.L. specifications. Drawings for the assembled cylinder, the component parts, and a bill of materials were submitted to the customer and approved.

One unresolved detail that remained, however. The amount of draw reduction from blank to finished shell diameter exceeded the industry-accepted limits of drawability for cold rolled steel. Among the key strengths of Larson Tool are innovations we have made in deep draw technology. Processes at the time “broke the rules,” but this draw had never been attempted. Some tangible evidence was needed before a large capital investment could be made.

Help was enlisted from an associate short-run metal stamper who had hydraulic draw press equipment suitable for the R & D work required. A scaled-down version of the shell was developed that proved the viability of the process. This success gave Larson the confidence needed to proceed with the project.

Temporary tooling was built and further development of the deep draw process was done. A set of prototype cylinders was produced and burst tested. Results indicated that the cylinder design exceeded U.L. burst ratings by a good margin. Prototypes were delivered to the customer in the spring of 1998.

Specifications for a press line to produce the new shell were developed by Larson in the spring of 1998. Budgetary numbers and a time line were presented to Larson management who, in turn, informed the customer that the project was ready to proceed. In June of 1998 the customer committed to the design of the new cylinder.